1. Field of the Invention
This invention relates to a method of improving the freeze-thaw stability of fish bait.
2. Prior Art Relating to the Disclosure
In the sports and commercial fishing industry it is common practice to preserve fish bait by freezing the bait to render them usable at a future time with a minimum of deterioration. Fish, such as herring and opelu (mackerel) and other bait fish, when thawed after being frozen, tend to become soft and are easily stripped off of the bait hook during trawling. This is frustrating to the sports fishermen and costly to the commercial fishermen. It is the usual practice for fishermen to thaw a frozen package of bait at room temperature for immediate use. In the course of one or two hours, the thawed fish bait becomes soft and will not stay on the hooks.
Formaldehyde has long been used to preserve tissue and toughen up protein material by "tanning." Formaldehyde, however, is toxic and cannot be used without killing the fish that consume the bait which are not caught. In addition to formaldehyde, solutions of borax, brine, sugar, milk and other treating solutions have been used through the years for preservation. One non-chemical method used today to improve the freeze-thaw stability of herring is to impound the herring from one to two weeks without food to starve them in order to reduce the enzymatic activity in their stomachs. They are then electrically killed and freeze-packed. This method is costly in terms of loss of fish and impounding time, especially when fish are running and the need for packing is immediate. For this reason a great many herring are freeze-packed green (i.e. freshly caught).
U.S. Pat. No. 2,693,417, issued Nov. 2, 1954, describes the use of triethylene glycol and other related materials as a solution preservative for non-frozen fish after treatment with formaldehyde. This treatment and preservation was designed to keep the fish bait for long periods of time at room temperature. In practice the process was limited to fish under 6 inches in length and was not considered non-toxic to fish life. The fish treated by this process also carried a distinct odor which is characteristic of methylation of proteineous tissues, an oder not desired by fish or fishermen.